Daughters of the sea
by Lollie057
Summary: Cleo and Katrine find out they are demigods. the children of a certain sea god, What sort of adventures will they go on. With Percy as a brother life can be very unpredictable... Rated T because of violence in future chapters Set from the end of the last Olympian and continues to the hero's of Olympus series .
1. Chapter 1

**Ok, so this is my first Percy Jackson fanfiction so I would appreciate any and all reviews. This Fanfiction is set from the end of the last Olympian or the last book of the Percy Jackson and Olympians series leads on to the heroes of Olympus books with some alterations to fit with the story. Some people may not like the changes to the story but please no hateful reviews but a would like some constructive criticism so I no what i need to improve on. Ok so now that's sorted on to the story... **

**Disclaimer:-**** I don't own any of the characters from Riordan's books that are in this story apart from the few OC that i have made up myself.**

**Percy's POV**

As he walked back to the doors to the elevator where his girlfriend Annabeth was waiting for him Percy thought about what his father had just said to him...

*FLASHBACK*

"Thank you Percy, for now i can finally claim my other two children." Poseidon said gratefully

"WAIT" Percy said in disbelief "I have to other siblings?"

"Yes, twin sisters, Cleo and Katrine." Answered Poseidon.

"And why didn't you tell me before." Demanded Percy Angrily.

"I wanted to make sure you were ready, and anyway I wouldn't have been able to claim them before now without Zeus punishing them." The god explained calmly.

Percy nodded in understanding though it still angered him know his father had kept something this big from him for so long. "How old are they?" He asked thinking back to when he first found out he was a demigod at twelve years old.

"Just turned fifteen" Poseidon replied, " They live close to your camp, You will meet them sometime next week near long island so be ready."

*FLASH FORWARD*

Percy shook his head, over whelmed with new piece of information. He had two younger sisters!

**Cleo's POV**

Cleo sprinted down the beach, her feet sinking in the soft golden sand of long island beach, as she raced her twin sister, Katrine to the water's edge. With a burst of energy she sped to the finish line only to find Katrine was already there. She stopped on the sand near the edge opposite where her sister was stood in turquoise shorts and a white t-shirt ankle deep in the water.

Using her fingers to pull the worst of the knots out of her wavy black hair Katrine struck a pose and bellowed. "I Katrine, have proved that my speed is far superior to all those to dare to oppose me, including my younger twin Cleo!"

"only by an hour!" Cleo protested before shoving her sister so that she toppled over and ended up sat in the cool green sea water.

Katrine pulled a face that sent Cleo rolling on the sand in a fit of giggles only to have her sister grab her arm and drag her so she was soaked from head to toe. Cleo pulled herself up so she was sat next to her twin. They sat there i silence the only sounds to be heard were the rustling of the surrounding trees, the screeching of the sea gulls the distant sounds of the traffic in new York and the sound of Cleo's dark brunette hair dripping into the shallows for five long seconds. One...two...three...four...five.

Both girls looked at each other before both sisters burst out laughing and splashed each other under the sun.

**Unknown POV**

Unbeknown to the children they were being watched by a figure stood in the shelter of the trees.

"Yes little demi-gods enjoy the heat while it last because once I get my hands on you there won't be a single soul able to hear you scream!"

**Well there you go. I'm sorry if this was a little long and boring but there's nothing i can do about it. Review and follow if you want another chapter and ill upload the next one if i get enough.**


	2. Chapter 2

**Firstly I would like to thank Sparky199 for helping me fill some holes in the plot and basically helping me add life to Cleo and Katrine and also for being the first person to review. Secondly I've been thinking about the way this story is heading and have realised that the first five or six chapters will just be introductory fluff but I swear on the River Styx hat if you bare with me the story will get better but I can't do anything about it otherwise the plot will not make sense. Finally Ive noticed even though I've had quite a few views but only one reviews and I would like to say it's really not that hard. So please once you've finished this chapter just spend a minute or two just telling me what you think of this chapter and if you have any ideas for the story in future chapters I would love to know. Ok now that's wrapped up here's the chapter.**

**Disclaimer- As much as i would love to own Percy and Co I don't. **

Katrine's POV

"Children, we're back!" Called the voice of the twins mother as an opened top cherry red Ferrari pulled up in front of the path down to the beach front.

The girls watched as the tall strawberry blonde woman stumbled down towards them in ridiculous sequined pink two inch heels and a matching frilly pink pencil dress. Katrine didn't know why she even bothered coming home her rich new husband Joseph (the twin's step-dad) would just wisk her away on another posh holiday again in two days time.

It wasn't that Katrine didn't like her mother but she was very absent minded and didn't understand that she or her sister didn't care for all the designer items she bought them; they just wanted to spend time with her. It was her new husband they didn't like. They refused to call him dad and if the had to talk to him (or about him) they would just call him Joseph. Reasons they didn't like him.. 1 He ignored them at all times. 2 they were sure he did everything in his power to keep their mother away from them. But they kept their mouth shut for their mothers sake.

The two sisters held tightly on to each other as they began to dread the scolding they would get of Joseph for getting their clothes wet.

As they trudged back to the car Katrine stopped, she heard rusting coming from the trees to her right. As she scanned the the surrounding area she saw a pair of glowing green eyes but after a few seconds they were gone. She felt Cleo place her hand on her shoulder.

"Are you ok Kat?" She asked quietly.

Katrine shook her head "I thought I saw something but i must have been seeing things.

Cleo lowered her brows in concern before following after their mother. Katrine waited a few seconds staring at the gap in the trees where she saw the eyes but after seeing nothing she shook her head again and ran to catch up with her sister.

During the next few days Katrine couldn't shake the feeling that she and her sister were being watched. That uneasy feeling lasted until her mother and Joseph left once more on a 'business' trip. Leaving the twins feeling slightly abandoned.

In an attempt to cheer themselves up Katrine and Cleo walked down to their favourite place; long island beach. But something felt wrong. The sky was empty of all life as if someone or something had scared away all the birds.

It wasn't until a huge monster charged out of the trees and down the beach towards Katrine and Cleo that the older twin realised that it was more than a feeling. Before she could react Cleo had grabbed her arm and pulled her o her feet and out of the way. Katrine watched in horror as a blob of illuminous green acid left a crater in the sand where she had been sat.

**Ok I really am sorry for this disgrace of a chapter but it was necessary for the next few chapters to make sense. But anyway thanks for reading now al thats left to do is press that little rectangular button at the bottom of the screen and leave a review telling me what you thought of the story and any ideas you would like to share with me or thing you think I could improve on. Im open to all suggestions. **


	3. Chapter 3

**I'm sorry but this chapter is basically just repeating what happened in the last chapter but from Cleo's point of view but with more of a description about the monster so please just bare with me it will get better in the next few chapters. Once again I would appreciate if people review and follow/favourite. Thanks.**

Percy's POV

As he sat looking out at long island beach Percy wondered how long it would be until he met his sisters. He wondered what they looked like, whether they were nice or not and , as much as he hated himself for it, whether they were strong enough to make is as demigods of one of the eldest Gods.

Hearing the sound of the conch shell behind him Percy stood up, brushed the sand of his blue shorts and walked towards the dining pavilion still deep in thought.

Cleo POV

Cleo, much like her sister also had a feeling something bad was going to happen. She had seen the shadows of a fat lady and her pet multiple times since the beginning of last week. Normally seeing shadows would scare anyone except en though the shadow of the fat lady was always the same her pet seemed to have to different forms. One form was a small Chihuahua a common house hold pet around this area, but it wasn't that form that scared her. The other form was that of a huge beast with two heads- she could only guess but one of which looked like a goats head the other she thought was a lion with a big bushy mane- and a tail that seemed to curve around the body on its own accord. As if the tail its self was alive.

Cleo new she should tell her sister but she didn't want to scare her. How would Katrine be able to sleep at night knowing they were being stalked by a fat lady and her pet Chihuahua that had the ability to turn into such a terrifying beast?

But it wasn't until she actually came face to faces with it that Cleo realised how fearsome and deadly the monster was...

After their mother and Joseph left the two girls walked down to long island beach in attempt to rid themselves of the feeling they were being abandoned. They sat down in the place where the gentle waters ran up and down the sand twinkling in the golden rays of the sun. It was a perfect day. But that was not to last much longer. After a few minutes of sitting talking the monster charged out of the trees and cam bounding down the beach towards them like a puppy chasing its ball that was rolling down the street. Only this beast was DEFINATLY NOT a puppy and its ball was the two girls relaxing at the bottom of the beach.

The like Cleo had thought had the head of a goat with long thick horns ending in wicked points that had the ability to spear strait through a person's body the other head a golden lion with a foaming mouth, sharp fangs and a grand mane. The tail was a snake. Bright green whipping around in an attempt to see( and taste) the two girls. Its fangs were long, pointed and the ends were dripping in venom. The beast turned to the side so the snake was facing the girls and Cleo watched almost in slow motion as the snake spat a huge blob of acid at the girls.

Cleo surged forward, grabbed the wrist f her petrified sister and pulled her to her feet. She watched as the illuminous green acid vaporizing the sand around where it had landed leaving a large crater in the ground where the girls had once been sat.

"RUN!" Cleo Shrieked

She raced into the shelter of the trees, unable to look back for the fear that she would see the beast hot on her trail. Preying all the time she was running that her sister was behind her.

**Thanks for reading don't forget to review**


	4. Chapter 4

**Ok this is where things start to get a little bit for interesting FINALLY. So I've come up with a little deal the more people that review the quicker i post the chapters. It's a win win situation. Anyway here's the next chapter. Remember to do your part of the bargain and review.**

Katrine's POV

Katrine took off, using her long legs to propel herself forward across the sand, up the beach and away from the sea. Only as she made it halfway up the beach did she realise that Cleo was not behind her. She skidded to a halt looking behind her franticly searching the beach for any sign of her sister. Half blinded with panic Katrine didn't notice the monster surging towards her on her left hand side.

Its large paws helped it balance on top of the sand meaning it didn't disturb the sand so it could sneak up on its prey making no sound what so ever. It reached it target and reared up on it back paws...

Sensing something Katrine turned to her left only to see the sight of the beasts golden underbelly as it brought is heavy front paws down on her head. Katrine's vision blurred and the ground seemed to tilt like it was one giant seesaw. She stumbled a few steps forward in dizzy attempt to get away before collapsing, unconscious in the sand...

Percy's POV

Percy tipped a section of his meal into the flames. "Hey dad, I just wanted to know, when will I meet my sisters? It's been a week since you told me they existed so why haven't i seen them yet? He muttered into the golden flames.

He walked over to his seat on the Poseidon cabin table with Grover and was about to sit down when Clarisse appeared in the door way "Chimera spotted on long Island beach, Its attacking two girls!"

Percy shot to his feet "My sisters!" he gasped before leaving a slightly bewildered Grover and his uneaten meal alone at the table.

He raced across the camp to get to the Pegasus stables before jumping on the back of his Pegasus Blackjack. "The long island beach quickly!" he commanded as the horse spread his wings and took to the skies...

Cleo's POV

It wasn't long until (Like Katrine) Cleo realised that her sister wasn't following her. Fearing the worst she grabbed a heavy fallen branch of the floor and rushed back down to the beach. She stood in the tree clearing only to find out she had front row seats to the horror that was watching Katrine being Knocked to the ground by the monster. In a blind rage Cleo charged at the beast using her branch to swipe, stab and hit its heads. But as the adrenaline rush began to wear off Cleo slowly realised that she couldn't fend off the monster forever. She wouldn't last much longer. A lone salty tear made a path down her pink cheeks. Her sister would have died for nothing.

**Just thought id leave you with that cliff hanger there. Wow it's nice to be able to write something that's actually interesting and isn't just introductory fluff even if it is quite a short chapter. Well Thanks for reading this more exciting chapter and don't forget to review.**


	5. Chapter 5

**OK my fifth chapter now, hope people are enjoying my story so far. The plots starting to progress so the chapters will be getting better from now on. Any way here's the next chapter and remember the more reviews I get the faster I update.**

Percy's POV

By the time Percy and Blackjack landed on the beach he saw one of the girls (the one with wavy black hair) was lying unconscious in the sand while the other girl (the one with dark brown hair and turquoise eyes) was trying to fend off the beast with nothing but a branch.

After a couple of seconds Percy identified the monster as a Chimera. He remembered that he had battled one on his first quest to retrieve Zeus' lightning bolt when he was twelve.

Seeing that the brunette girl was doing okay for the moment, Percy went over to the other girl who was lying unconscious a few steps ahead of him. He knelt down beside her and checked her wrist and the side of her neck. He could feel a stable pulse so now he could turn his attention to the real problem. THE CHIMERA.

Percy saw the girl begin to falter. Her swings becoming sluggish as she struggled to swing the branch. The monster was pushing her backward. If he didn't help her soon she would be overpowered.

He pulled the pen out of his shorts pocket and clicked it so that his bronze sword, Riptide, was in his hand. Percy held the blade out in front of him and charged...

Cleo's POV

Cleo didn't see the black, winged horse land on the beach behind her, nor did she see the boy with messy black hair and sea green eyes running towards her with a bronze sword in his hand.

No Cleo was too busy trying to stop herself being eaten alive by a goat a lion and a snake. Suddenly, out of the corner of her eye, she saw the goat head fall to the floor by her left foot. She glanced to her left to see the boy; his sword dripping with a green liquid she could only guess was the monsters blood.

Cleo and the boy edged around so that they were stood on opposite sides of the beast. The boy pared against the snake tail. Fangs against sword. Cleo took on the lion head, hitting it with her branch until it was in a daze. She nodded at the boy and with one quick flick of his razor sharp blade the lion head dropped to the floor staining the surrounding sand with green blood. They then teamed up on either side on the snake until the snakes head landed on the sand in between them.

The beast's headless body dropped to the floor. Cleo flopped down on the sand next to it breathing heavily.

"What *gasp* was that thing" She asked the boy breathlessly.

"That was the chimera, son of echidna" replied the boy looking at her " I'm Percy by the way" He said holding out his hand.

"I'm Cleo." She said before taking his hand and pulled herself to her feet. She wiped her hand on her jeans "who's echidna"

"Echidna's...WAIT" "You haven't seen echidna yet?" questioned Percy.

Cleo shook her head "Why, should I have?" She asked.

"Oh no oh no oh no" muttered Percy just loud enough so Cleo could hear before rushing off to Cleo's sister was led unconscious.

Cleo chased after him wondering what possibly could have gotten him so worried. When she could up with him she saw he was stood where she had watched her sister fall to the floor earlier. There was only one problem.

Her sister wasn't there...

**This chapter a little bit longer to make up for the last one which was a little but short. Thanks for reading and don't forget to review.**


	6. Chapter 6

**Ok chapter six, Things are getting a lot more interesting now but I've noticed that I've had quite a lot of people reading my fanfiction yet I've only had a few reviews. Come on, it's really not hard. You just press the little review button at the bottom of the screen and tell me what you think of the story so far. Whether you're enjoying the story so far or not, I don't care. It's the fact that if it's a good review I know people are enjoying it or if its a bad review I know what I can do to make it better. So anyway please review and here's the next chapter.**

Percy's POV

Percy stared at the indent in the sand where Cleo's sister had, only five minutes ago, been lead unconscious. He now knew how Grover had felt when he didn't get Thalia back to camp all those years back before he even knew he was a demigod. Percy felt like a failure. If his suspicions were right and echidna had gotten hold of the girl she was as good as dead. The only thing he could do was make sure that Cleo got back to camp in one piece.

He stood up and looked up at Cleo. He was surprised to see that she looked fine. No one could have guessed that she had just found out that her sister had just been taken by the monster mother. Strange, did Cleo not care about her sister? Did she know this was going to happen? No, Percy couldn't think like that. Of course Cleo cared about her sister. And how could she have possibly known she was going to be taken. No she was just in shock that's all.

"Percy" Cleo asked "Why are you staring at me?"

Percy turned a deep shade of red. "Sorry I was thinking about something." He muttered.

Cleo nodded "So what do we do now."

Percy took her hand and started leading her back towards Blackjack. "I get you back to camp."

They flew back to camp in silence that just made Percy feel worse. He tried to block out the guilt and instead tried to think about Annabeth, he hadn't spent much time with her lately as she claimed to have a project she was busy with which Percy couldn't help feel down hearted about. It was nearly a year now since they had started dating and Percy wanted to do something special but with Annabeth being busy he was starting to think that she would be too busy to do anything.

Percy's train of thought was broken as they landed outside the Pegasus stables. He heard Blackjack grumble something about how hard it was to carry two people on his back and fly in a straight line. Percy ignored him and started leading Cleo across camp towards the big house. Chiron would want to hear about what had happened on the beach.

He tried to ignore people staring at them and whispering to their friends as they walked past. Once again Percy found himself searching through the crowd that was starting to form for Annabeth but there was no sign of her. Percy's heart sunk a little bit more.

When they finally reached the big house Percy pushed open the door and lead Cleo inside and saw Chiron and Mr D were playing some sort of card game. When they entered the room both men looked up from their cards.

" Peter Johnson, of what do we owe the displeasure of this visit" Said Mr D.

Percy ignored the God. "Chiron I need to talk to you."

The centaur looked between Percy and Cleo before indicating for them to follow him outside.

"What is it?" Chiron asked once all three of them were stood outside.

"This is Cleo, she was attacked by the chimera today "Percy started.

The centaur nodded slowly.

"She has a twin sister..." Percy trailed off.

"And where would she be?" asked Chiron.

"That's what I needed to talk to you about" Percy swallowed "She's been kidnapped by Echidna..."

**And there you go I put a little Percabeth in there for people. Thanks for reading and don't forget to review.**


	7. Chapter 7

**Hi guys look I'm so sorry this chapter is almost two days late but I've been really busy these last two days and have only just had time to update this now but anyway. This is chapter seven and the pieces are starting to come together now so I know what I want to happen in the story now so the chapters after this one (which is mostly just talking) should be better now. I'd also like to say thank you once again to Sparky199 who basically wrote the prophecy for me(I was totally brain dead and couldn't think of one for myself) Anyway here's the next chapter, don't forget to review.**

Cleo's POV

Cleo stood there I silence, watching as Percy and Chiron discussed what they were going to do about her sister in hushed voices. It irritated Cleo that no one was taking any notice to her. It wasn't that she was being selfish but they were discussing HER sister but they weren't even letting her listen to what they were saying. It was as though she wasn't even in the room.

"Ok, I'm sorry for interrupting your private conversation but it might be helpful to tell you that my sister isn't dead."

Both Percy and the centaur turned around and looked at her in shock.

"And how would you know that child."Chiron asked.

Cleo shrugged. "The Oracle told me a few days ago"

Percy turned to the centaur. "How could she have spoken to Rachel when she only just got to camp and more importantly how does she even know about the Oracle in the first place?"

"I honestly have no idea?" The centaur turned back to Cleo "Care to enlighten us"

Cleo took a deep breath. "Last week I kept seeing shadows of the creature that attacked me and my sister today. I wanted to know what it was so I walked down to the library in town to see if I could find out what it was." Cleo looked up and a saw the centaur nod in understanding and gestured for her to continue.

"On the way back home i bumped into a girl with curly red hair. I muttered an apology and was about to continue on my way when she turned around and gripped her hands tightly on my shoulders. Her eyes and mouth started emitting this green smoke. She spoke in this raspy voice that almost sounded like three woman talking at the same time."

Percy interrupted "what did she say"

Cleo gave him a look "I was getting to that." She snapped before continuing. "She said something that sounded almost like a strange poem, it's kind of hard to remember. I think it went like this;

Children of the sea will live in two worlds, letting destiny twist and twirl, creating a resistance from afar, Fight until they are at par, one way or another the world will fall, with seven others they shall answer the call, and children of destiny reunited after all."

And then she went back to normal and walked away as though nothing happened and walked away" Cleo finished before looking up to see what Chiron's and Percy's reactions were.

"Was that..."Percy trailed of looking worried all of a sudden.

The centaur nodded looking equally worried and beckoned the two children to follow him.

It was getting dark outside and Cleo could hear laughter coming from near the woods. As she got nearer she saw loads of other kids were sat laughing and talking around a campfire that glowed golden. Chiron stood in front of everyone and tapped his hoof twice on the ground. Everybody looked up and immediately the area went quite.

"I have something very important to tell you all!" announced Chiron. "The Oracle has recited another Prophecy.

**Please review and tell me what you think. Also if anyone has any ideas about thing that could happen or even any questions just put them in a review and ill read them and try to answer/ incorporate them the best I can. Thanks for reading. **

**Also I'm starting another Percy Jackson fanfiction called 'a rose to save the world' if any one would like to check that out and tell me what you think that would be great. And just cause i'm starting another story doesn't mean i'll forget about this one it will still be updated every two days like it has been since I started.**


	8. Chapter 8

**I'm putting this chapter up a second chapter today to make up for the other one being so late. Anyway I'm sorry for that but here's the next chapter. I hope you enjoy it. Don't forget to review **

Percy's POV

Percy was still amazed at how quickly everyone quietened down when Chiron banged his hoof on the ground. It just showed how much everyone at camp Half Blood respected the centaur.

Annabeth was the first to speak. "Chiron, if the oracle has recited another prophecy how come at least one of us here at camp heard it."

Chiron looked at Percy's girlfriend "The answer to that is simple, because the prophecy wasn't spoken at camp."

Percy watched as Annabeth scowled at the ground making him smile. She hated not knowing things (It was one of the perks of being daughter of Athena)

"But that means there's another demigod that needs to be brought to camp" She said.

Clarisse stood up "Chiron we have to send someone out to get them, it's dangerous for demigods to be left alone." Clarisse may be heartless at time but she does have her moments where she shows she cares.

Chiron shook his head "No need Percy saved her from a Chimera attack earlier today." He then stepped aside to revile Cleo standing in the shadows behind him.

Everyone's attentions turned to Cleo making her go red and look really uncomfortable. A few people from the Hermes cabin sighed a little. Most of the new demigods ended up in their cabin so it was a little bit cramped in there. Percy himself had spent some time in the cabin when he first came to camp so he knew how bad it could be.

"Who's her godly parent?" asked someone from the back.

Chiron ignored the question "Rachel." HE said looking over to where she was sat between Annabeth and Grover. "Could you perhaps share the prophecy with the rest of the camp?"

Rachel nodded and her mouth and eyes beginning to emit green smoke. She spoke the prophecy in an old echoed voice.

Percy listened again to the prophecy trying to make sense of the cryptic poem. As the oracle finished the green smoke started to fade and Rachel fell backwards. Annabeth and Grover stepped forward to catch her before settling her back in her seat.

The area was filled in an awkward silence as everyone took in the prophecy. A few people muttered to each other in confusion.

"What does that mean?" Yelled someone from the Ares cabin. A few people muttered there agreement.

"It means Percy has a sister." Said Annabeth just loud enough for people to hear...

**Thanks for reading. The next chapter in two days time please review.**


	9. Chapter 9

**Ok this is chapter 9. Hope you guys enjoy it.**

Katrine's POV

Katrine woke up in a dark cave. Her head was throbbing. She gingerly touched her fingers to a spot on the back of her head. She felt a large lump that was tender to touch. Her vision focused and Katrine saw a large reptilian woman sat in the entrance to the cave tending to a metal pot that was suspended over a campfire.

The woman turned around. Her eyes were emerald green with thin black slits for pupils. Much like the eyes of a snake. She had stringy, short black hair and instead of legs she had one large snake trunk that supported her. She had green scales covering her body from the waist down and golden armour covering her chest and stomach. Just the sight of this woman made her feel uneasy.

"Finally, you're awake." Hissed the woman her black forked tongue flicked around her mouth as she spoke.

Who are you and why am I here?" Demanded Katrine as she pushed herself of the cold stone floor so she was standing face to face with the snake woman.

"I am Echidna, mother of all monsters and well you are here because I want some information that I believe you have." Echidna said proudly.

"What sort of information would that be and what makes you so sure I will tell you." Asked Katrine boldly

"Just one little question my dear, that is all." Echidna said her voice dripping with false sweetness.

"And what makes you so sure I can answer that question"

"Because five years ago I met your brother and well I want revenge on him but you see your brother is protected in a place called camp half blood. I do not know where that is and you're going to tell me." Echidna answered smiling coldly.

"For one I don't have a brother and even if I did I wouldn't tell you where he was, and for two, I've never heard of this camp half-blood in my life so I'm sorry but I can't answer your question." Replied Katrine.

Echidna smiled deviously "Ok that's fine you just keep that information of yours a secret for now but don't worry I'll get it out off you eventually" Echidna walked off to the back of the cave. "I knew I should have asked your sister" She sighed to herself "Oh well too late know"

Katrine held her breath "Where is my sister?"

Echidna turned back to face Katrine, an evil glint in her eye. "Oh I wouldn't know she could be anywhere. Dead or alive. I really don't know"

Katrine screamed and ran at her captor. "If you've killed my sister I will kill you"

Echidna just swiped back her hand sending Katrine flying back across the room. She hit the cave wall with a satisfying crunch. Katrine tried to push herself up but found she couldn't when putting pressure on it caused pain to shoot right through her right wrist.

"Oh I wouldn't try that again my dear or something worse than your wrist might get broken"

Tears formed in Katrine's eyes. "If you've hurt my sister..."

Echidna just laughed and set off to the back of the cave again.

Katrine gritted her teeth, tears forming in her eyes. She cradled her broken wrist trying to ignore the throbbing pain in both her wrist and her heart. Her sister couldn't be dead could she?

**And there you go. I hope you like it and don't forget to review and tell me what you think.**


	10. Chapter 10

**I know I'm sorry this is a terrible chapter but no matter how much I tried I couldn't get it right I'm sorry.**

Percy's POV

Percy didn't know what to say. Of course he did have his suspicions when he first saw here. And Poseidon did say he would meet his sisters on the beach but he still couldn't believe his sister was here. Yet Percy couldn't help wondering, what had happened to his other sister, Katrine. Was she even alive?

He just stood there listening to the silence for what felt like an eternity. Everyone's faces were different. Shock, worry, happiness some were just blank. But no matter what the reaction everyone's eyes were on Percy. He shifted uncomfortably. He didn't like all this attention.

Cleo was the first to speak, her blue eyes wide with surprise. "Wait" she held up her hand. "So Percy's my brother, how is that possible, my mother never had any more children." Percy saw her eyes widen even more as she put the pieces together. "Is this something to do with my dad?"

Chiron nodded "It's late now, Percy will show you to your cabin, get some sleep, I'll explain it all in the morning."

Cleo nodded and looked at Percy. Percy indicated for her to follow him and they walked over to the Poseidon cabin. Percy heard her gasp as Cleo saw the cabin. He grinned to himself; Percy remembered when he first saw the shell encrusted walls of cabin three.

Percy opened the door and lead Cleo inside. He climbed into his bunk and shut eyes.

Annabeth's POV

Annabeth watched her boyfriend lead Cleo across to their cabin. She turned around and was about to head back to her own cabin when Chiron called her over.

"What's up?" She asked.

Chiron grimaced. "I fear something is going on."

Annabeth nodded. First the Gods had gone silent, then this girl had turned up out of nowhere. Something was definitely going on.

"I need you to keep an eye on Cleo."

Annabeth nodded and turned back to her to go to her cabin.

"Oh and one more thing, Cleo has a sister called Katrine."

"Where is she?"

"She got captured by Echidna"

Annabeth nodded again. The odds were she was dead.

**I know, worst chapter so far sorry. Anyway thanks for reading don't forget to review.**


	11. Chapter 11

**I'm putting up a chapter today because the other one wasn't very good and I figured you guys would prefer a chapter with slightly more substance. But first I would like to say thanks to danelekenrik and sparky199 for reviewing not at all long after I put the chapter up and for all those people who have reviewed, favourited or followed since I've started this story, you guys make my day. Thanks for that. Anyway here's the next chapter.**

Katrine's POV

It had been a good two or three days (though Katrine had lost count) since she had been captured and Katrine was starting to lose hope of ever getting out of the cold dark cave she was held prisoner in.

She had explored the whole cave but there was no other escape route other than the front entrance which was blocked off by a large boulder. The boulder was extremely heavy and Katrine couldn't even shift it an inch (She had tried many times). The only time it was moved was when Echidna was boiling rabbit for the disgusting rabbit stew, Katrine had been forced to endure every mealtime since she had been brought to the cave, so the steam could escape. Once again Katrine had tried many times to sneak past Echidna but she was always caught and punished for trying.

Katrine's body was covered in bruises and cuts that Echidna had inflicted on her for either trying to escape or refusing to give the information that Katrine didn't have in the first place. Katrine knew she had to get out of there. And she had to do it tonight!

Echidna marched over to where Katrine was sat on the floor, her scaled tail dragging in the dirt on the ground. "Just tell me where camp half blood is and I'll let you go" She demanded for the millionth time.

Katrine glared at her captor. "I told you, I don't know where this stupid camp is, can't you get that into your think skull!"

Echidna scowled before resuming her falsely sweet tone. "Now, now dear, no need to get personal, all you have to do is tell me where the camp is. Who knows, you might even help your sister by telling me."

Katrine faltered, her eyes softening for just a second. Where was her sister, was she even still alive? Katrine shook her head slightly and her green eyes hardened again. "Oh, shut up with your useless threats. I've searched this whole cave and there is no sign of her sister anywhere. You must be really stupid to think I'd fall for that trick!"

Echidna hissed in annoyance and lashed out leaving an angry red mark on Katrine's cheek and causing her to fall to the floor landing on her broken wrist. "Stop lying to me girl!" She yelled before storming over to the back of the cave.

Katrine curled up in ball on the cold stone floor cradling her broken wrist. She had to get out of here TONIGHT!

Jason's POV

Jason sat in is Praetors seat with his head in his hands. He had spent the last hour listening to Reyna and Octavian argue about who was going to storm Echidna's base.

"NO!" Reyna yelled "I will go ALONE."

"No, let me lead an army to the cave, strength in numbers!" Octavian retaliated.

Jason sighed. Octavian really would do anything for the change to command the legion. He really did love being in control.

"NO, too many Romans in one place will alert all the nearby monsters of our presence. I must go alone" Reyna demanded.

Octavian looked defeated for a second but it didn't last long. "Yes but, there will be more soldiers to fight them"

Reyna scowled at Octavian's resistance then opened her mouth to argue back but Jason couldn't take it anymore. This argument had gone on too long.

"Enough!" He bellowed taking his head out of his hands. They both went quiet and looked up at him. "I'm the one who spotted Echidna there for I shall be the one to go in the mission alone"

Reyna gave him a small smile. Jason guessed she was just happy that Octavian didn't get his way. Octavian glared at the ground.

-Line break-

Jason waited till night fall so the darkness would hide him from any monsters. He walked out of the tunnel and away from Camp Jupiter. He rubbed his golden coin nervously as he walked. This could be a tough battle especially if Echidna's child the chimera was there. This could end very badly.

He finally reached the cave. It was set on the edge of the woodland area. There was a large boulder in front of the entrance. The only problem is it was set on the inside. Jason slowly walked closer to the cave and spotted a small gap between the boulder and the edge of the cave entrance. It was very narrow just wide enough for a smaller person to squeeze through. For a second Jason wondered how it had got there but he didn't question it. If anything it made his job easier. All he had to do was squeeze through, kill Echidna in her sleep then leave.

He took a deep breath and took his golden coin out of his pocket. He flipped it and caught his Gold sword. He started forward and was about to go into the cave when a girl with black hair came out of the cave...

**Thanks for reading. Please review cause I love hearing what you guys think.**


	12. Chapter 12

**Thanks again to all those who reviewed my last chapter you guys are all awesome. I went back to school last week so chapters might be later than usual because I'll have homework to do as well. Anyway here's chapter twelve hope you enjoy.**

Katrina's POV

_A few hours earlier_

Katrine began hatching a plan for how to get away from Echidna. She couldn't do too much because of her broken wrist but if she thought out a good enough plan she should be able to get out without any trouble.

Firstly she searched the whole cave to look for something she could possibly use to aid her in her escape. She found a small pile of rabbit bones in the back of the cave. Katrine picked up a few and slipped a few in her now tattered shorts pocket.

Katrine waited till Echidna was sat in the middle of the cave entrance. Echidna was busy preparing rabbit stew so she didn't notice when Katrina crept past her and placed the bones by the side of the cave entrance.

After they had eaten Echidna rolled the boulder back in front of the entrance but it was stopped from closing all the way by the rabbit bones. It left just enough room for Katrina to fit through but not enough for Echidna to notice the gap.

_Back to now_

Katrine waited for Echidna to go to sleep then slipped unnoticed out of the cave. She squeezed through the gap and was about to run away when she spotted a blonde boy stood outside the cave.

"Who are you?" She asked.

"My names Jason, you shouldn't have gone in that cave, there's a dangerous monster inside" Jason warned.

"I think I noticed." Replied Katrine scowling.

Jason sighed. "Who are you?"

"What's it to you"

Jason sighed again and rolled his eyes. "Whatever, just stay out here, I'm going to go kill that monster"

"ERR No!" Katrine answered. "Echidna has kept me in there for days now; I'm coming in there with you."

"No you're not, it's too dangerous and you don't have any weapons to fight with" Answered Jason.

Katrine pointed to the silver and green blade in Jason's belt. "Then give me that one."

Jason glared at Katrine clearly getting annoyed with her ignoring him. Eventually he gave in and handed her the sword. It was silver with green swirls over the handle. It had a green gem on the bottom that glowed in the darkness and wave designs carved on the blade.

Katrine held it in her hand and it seemed to be the perfect weight for her. Jason lead the way in and Katrine followed him inside.

They walked around so they were on either side of Echidna's sleeping form. Jason brought his golden blade down on the monsters scaly green neck. The blow should have taken her head off but instead it just bounced harmlessly of her. Echidna hissed and woke up. She looked around and spotted Katrine and Jason.

Echidna swung her tail around in a circle Katrine leaped in the air just clearing it. Jason stepped back searching for a weak spot but neither he nor Katrine could spot anything. They both slashed at anything available but they couldn't make a mark on her armour like scales.

Echidna brought her fist down over Jason's head but he leapt up and used Echidna's arm as a ladder and stood balanced on her neck covering the monsters eyes with his hands. Echidna hissed and swiped around with her claws. They found their mark making three long and rather deep gashes on Katrine's forehead. Crimson blood came rushing down her face, getting in her eyes making it hard to see.

Echidna threw her head backwards sending Jason flying and hitting the wall. He sat there looking dazed but it didn't look to bad. Katrine struggled to use her weapon with her left hand.

The battle raged on for another hour, Katrine and Jason getting more and more beat up and exhausted but Echidna staying on strong with not a scratch on her body.

Katrine could feel blood pouring like waterfalls from several cuts and scratches on her body. Her eye sight was blurry from a mixture of exhaustion and the steady blood stream of blood pouring from the three deep cuts on her forehead. She struggled to dodge Echidna's attacks and her moves got more sluggish.

Jason was panting but doing better than Katrine. She guessed he had gotten more practice at this sort of thing; he wouldn't have come here if he didn't.

Echidna charged forward knocking Katrine to the floor. Her sword skidded across the stone floor away from her. Her legs were too shaky to hold her wait so Katrine tried to crawl across the floor towards where her sword was. She couldn't move very quickly because of her broken wrist and various cuts and bruises on her body.

Echidna grabbed her legs dragging her backwards so she was just feet from her weapon but so it was just out of her reach. Her finger tips clawed at the ground in a mad attempt to get away but Echidna was too strong. Katrine was dragged backwards across the cave so the already faint glow of her sword got fainter and fainter.

Katrine looked round the cave for anything that could help her get away but it seemed even Jason had left her. Echidna leaned over, her claws and fangs bared.

Just as Echidna's claws closed in on Katrine's chest her sword came skidding across the floor towards her. With her last ounce of strength Katrine drove her sword underneath Echidna's scales just piercing her heart.

Echidna exploded into golden dust that covered the cave floor. Katrine looked over and nodded her thanks to where a very bloody and battered looking Jason was stood and nodded her thanks before her vision blurred and she blacked out.

**And there you go guys and extremely long and interesting chapter. If you liked it please review because it really does make my day when I get to read what you guys think. Anyway thanks for reading, stay awesome. **


	13. Chapter 13

**Hey guys. First I would like to apologise for how late this chapter is but I moving house over the next few weeks so with all the moving, lack of the internet at the new house and the school homework I have to keep up on too, I have very little time to put chapters up at all. In fact it's a miracle I even managed to get this chapter up at all. But I have not forgotten about this chapter and will try to put up a chapter whenever possible. **

**Also I would like to say thank you to all those people who have reviewed, followed, favourited or just taken the time to read my story. You guys are all awesome. Anyway enough of me blabbering, on with chapter thirteen.**

Cleo's POV

Cleo woke up to the sound of waves lapping against the sea shore. She opened her eyes and smiled. Cleo had been staying in the Poseidon cabin for a good few days now and she wasn't over exaggerating when she said they had been the best few days of her life.

Percy and Annabeth had been so nice to her and did their best to make sure Cleo was too busy to worry about her sister. Annabeth had taught her Ancient Greek and Percy had trained her to fight and taught her to ride the beautiful Pegasus at camp. It hadn't taken very long for Cleo to become very close with the two and now couldn't imagine life without them. She just wished her sister could be there to share it with her.

Katrine still hadn't turn up yet. Both Percy and Annabeth did their best to act optimistic but Cleo could tell that they both were pretty sure she was dead. Though Cleo knew that wasn't true.

Last night she had had a dream. She saw her sister fighting alongside a boy with blonde hair and wearing a purple T-shirt. The boy had a blue tattoo on his left arm, a picture of an eagle with SPQR written underneath it. They were battling a lizard woman who Cleo guessed was Echidna. Her sister was beaten up with cuts and bruises covering her tanned skin. She was badly wounded but she wasn't dead.

Cleo climbed out of her bunk and dressed in a pair of blue jeans and her orange camp half-blood T-shirt and slipped on her black converse. She was about to head out for training when she realised. Cleo couldn't her Percy snoring in the bunk next to hers. Usually Percy slept much longer than Cleo and should still be asleep now. Only he wasn't and his bunk was made as though he had never slept in it at all.

Frowning, Cleo left the cabin and walked down to the Athena cabin to see if Annabeth had seen him.

Annabeth grinned when she saw Cleo. She was working on Daedalus' laptop but shut the lid when Cleo walked in. "Ready for your sword training?" She asked.

Cleo shook her head. "You haven't seen Percy have you?"

Annabeth frowned. "No, he's usually still asleep at this time."

"Yeah, but he's not in his bunk and the bed doesn't look like anyone has slept in it." Cleo said starting to get worried.

Annabeth stood up quickly. "Oh, something's wrong here, I walked him right outside your cabin last night and watched him go in. There's was no way he could have been attacked without you hearing it."

Cleo nodded. Something defiantly wasn't right. "We need to go and see Chiron."

They went over to the big house and explained to Chiron what was going on. He looked just as worried and ordered them to search all around camp and the surrounding area.

Cleo and Annabeth split up, recruiting as many people as possible to help them. Cleo told Connor and Travis Stoll and the rest of the Hermes Cabin, She got Katie Gardener and the Demeter cabin and Will Solace and the rest of the Apollo cabin to help her. They were as worried as her. They had known him for longer than Cleo and respected Percy greatly.

They searched the whole of the forest and the rest of the camp but there no sign of the son of Poseidon. Annabeth and her gang hadn't had any luck either.

Cleo Iris messaged Thalia and the rest of the hunters and asked them to keep a look out for Percy. Even they looked concerned for him.

That night Cleo collapsed in her bed. Her cabin felt empty without her brother. She dreaded tomorrow when she and Annabeth would have to tell Percy's mother.

**And there you go. Thanks for reading. Please review cause I love hearing what you guys think. Until the time folks.**


	14. Chapter 14

**Hey guys, I'm back. Sorry for the delay but I have, once again, been busy packing ready for moving on Saturday. I'd like to say thanks to everyone who has liked or reviewed this story, you guys are awesome and make me want to keep writing. Anyway, here's chapter please enjoy and review to tell me what you think.**

Cleo's POV

Cleo woke up and immediately looked over at Percy's bunk but there was still no sign of her brother. "Oh Percy." She muttered to herself. "Where are you?"

After showering and changing into a clean camp T-shirt and a pair of jeans, Cleo met up with Annabeth and Argus in front of Thalia's tree. Annabeth's eyes were red and blood-shot from crying and she looked like she hadn't slept a wink. Cleo really couldn't believe that Percy would leave camp without at least telling his girlfriend first.

"You ready to go?" Cleo asked.

Annabeth nodded and got into the back of the van. Cleo followed and Argus climbed into the driver's seat. The journey was long and awkward and Cleo was glad when the journey was over. She was starting to think that being a demi-god wasn't that great. She had lost both her brother and her sister in less than a week. To put it lightly being a demi-god sucked.

They walked up to the apartment. Annabeth rubbed her eyes and tried to pretend she hadn't been crying. Cleo knocked on the door.

Sally opened the door and smiled when she saw them. Cleo managed a small smile back but she felt terrible.

"Hi girls, come in" Percy's mum said opening the door wider.

They both walked in and sat on the sofa opposite where Sally and Paul sat.

" Hey Sally, Paul." Said Annabeth. "We need to talk to you, it's important."

Sally's smile faded as she realised that they came with bad news. "Where's Percy?"

Cleo swallowed. "That's kind of what we need to talk to you about."

Annabeth explained as quickly as she could what was going on and Cleo watched as Sally's eyes filled with tears.

Paul , who didn't look much better, pulled her into a tight hug.

"We've got everyone out looking for him, if we find him you will be the first one to know." Cleo said trying to comfort them.

Paul nodded.

"We'll go and give you some time to yourselves." Annabeth said standing up, tears forming in her eyes again. Cleo put her arm around the daughter of Athena's shoulders and led her out the room.

"Are you OK?" Cleo asked.

Annabeth sniffed and nodded. They got back into the van and drove back to camp.

**Yep , mostly monologue but you know. Anyway thanks for reading and please review. **


	15. Chapter 15

**Yay, I managed to find time to put up another chapter today. I've had like no spare time what so ever. We've been moving boxes from one house the other and I've been tackling homework no stop, but I've got some time now so I thought I'd put up another chapter for you guys, so I guess you're welcome. Anyway thanks to all you guys who have followed or liked this story. But I've had no reviews. : ( Please guys, all I'm asking for is one little review. Please?**

Katrine's POV

Katrine woke in a large white room. It looked like some sort of infirmary with two of the walls lined with crisp white beds. Most were empty but some contained kids, some that looked to have broken bones others seemed to have, stab wounds? That's what it looked like anyway.

Her head was almost numb to the point she couldn't feel anything but pain. It made it hard to think straight. She could feel a bandage wrapped tightly around her forehead and her blood stained shorts and T-shirts hanging loosely of her now thin body. She shifted and attempted to climb out of her bed but had to lie back down again as a wave of dizziness fell over her.

Katrine heard footsteps from the other side of the room and strained her neck to see who it was. It was Jason and another girl she had never seen before with long black. They were both wearing some sort of white toga thing lined with a purple ribbon around the edges of the fabric. They came to a stop at the foot of her bed.

"Glad to see you have finally woken up" Said Jason smiling. The girl next to him studied Katrine with her piercing amber eyes.

Katrine gave Jason a small smile then turned to the girl. "Who are you?"

"I am Reyna, daughter of Bellona." The name Bellona was said with such respect that it made Katrine think that this Bellona was a very important woman that she should have heard of but the name didn't ring any bells.

"Who?" she asked hoping that she didn't sound too stupid.

"Bellona, Roman goddess of war." Reyna answered, a faint smile playing at her lips.

All this did was confuse Katrine more so Jason ran through the whole Roman Gods and Demi-god thing.

"This is camp Jupiter, the only safe place on earth for Demi-gods." Said Reyna proudly.

Katrine's sea green eyes lit up. "So is my twin sister here too?"

Reyna looked at Jason a worried look on her face. She muttered something under her breath. Jason went pail and shook his head.

"I'm sorry, no one new come in for months." Answered Jason.

Katrine's eyes dimmed, her sister was most likely dead.

"We'll leave you to gather your thoughts. Come and meet us at the large white building at the top of the hill." Reyna said. "There are some clean clothes in the cupboard next to your bed if you want to change." Then they were gone.

Katrine quickly changed into the black leggings and Purple T-shirt that Reyna had left out for her and slipped on some white converse that for some reason fitted her perfectly. In the back of cupboard was also a flask. On it was a label that said 'drink all the nectar to heal all injuries.' Katrine opened the lid and sipped the golden liquid. It tasted like blueberry muffins. She smiled and drank the rest of the sweet tasting liquid and left the infirmary.

She walked up the path staring in awe at everything she saw. She passed strange people with goat legs and others that were slightly transparent and silvery like ghosts. She reached an open barrier and was about to walk toward the large white building up ahead when she heard a voice.

"Walk no farther."

Katrine looked around. "Who said that?"

"I said stop right there!"

Katrine looked around but couldn't see anyone, just a strange looking statue by the barrier.

"Who said that?" Katrine repeated.

"I'm over here, can't you see me waving at you?!" Demanded the voice.

The only thing that could possibly be talking was the statue. "Are you talking?" She asked to the statue.

"Finally!" said the statue. "What does it take to get noticed now a days!"

**And there you go. Please review, I need to know what you guys think to know whether I doing good or not. Please.**


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